I don't think this needs to be anywhere near as complicated as people make out.
People should be free to express their opinions. Other people should be free to disagree.
Free speech should only be restricted by law in very limited situations, such as when it crosses the line into incitement of hatred, or harassment directed at an individual. The law should be clear about what constitutes incitement of hatred, or hate speech, so that people can't simply claim that any disagreement with their point of view amounts to hate.
Yes, there may be some consequences to exercising your right to free speech, even if it falls short of hate speech. If you say that Hitler had the right idea about some things, even if you're referring to his views on eating animals, you shouldn't be surprised if people form a negative opinion of you. However, nobody should be experiencing negative repercussions in either their personal or professional lives for stating simple facts such as "humans cannot change sex" or saying that they do not share a particular belief, for example, around gender identity.
And the right to free speech should be equal for everyone. It shouldn't be that people from certain minorities can say what they like but the majority have to shut up. We hear so often that if someone has "privilege" they should keep their opinions to themselves and let others speak. I find the suggestion that someone like JK Rowling should be quiet and listen to trans people, on the basis that they are a marginalised minority and she is a rich and powerful woman, totally appalling.
When I express my views on the clash between trans rights and women's rights, it is in my capacity as a woman. I shouldn't be prevented from saying what that means to me just because of how someone else identifies. They can identify however they like but they must accept that other people cannot be forced to agree. Particularly when the identity that they are claiming includes me, but I don't want to be force teamed with them.